Method for forming a linear combination of frequencies and apparatus for carrying out this method



Feb. 12, 1957 w. IANOUCHEWSKY 2,781,450 METHOD FOR FORMING A LINEAR COMBINATION OF FREQUENCIES AND APPARATUS FOR CARRYING our THIS METHOD Filed April 30. 1953 3 Sheets-Sheet l 1 Generator Generator Generator Q 61 fix fig Modulator Modulator 1 r1 n, R M r; R q r l t I Filter Filter l r B1 B:

l v (Fx m Modulator (Fx Fe) filter Generator Generator Generator E1 E2 x i I Eat Modulator 1 Modulator "'1 '2 l l 1 Filter Filter Generator '1 '2 l l l-fa rlouulotor Modulator (F m '1' "fl? filter Filter B'q 3'; (Mat t {la-to Modulator Filter (fiu'fvfz') Modulator "5' v B5 "4;

Fre uenc (f R l (f, 5 g u 1 l l3 Flller 0 o INVENTOR Wlalllmlr lanouchewskg Feb, 12, 1957 w. IANOUCHEWSKY 2,781,450

METHOD FOR FORMING A LINEAR COMBINATION OF FREQUENCIES AND APPARATUS FOR CARRYING our THIS METHOD Fig. 3

Genet-afar Gener wladiagir 'aINVENTOR M V M l ORNEY W. IANOU CH EWSKY Filed April 30. 1953 S Sheets-Sheet I5 Generator fienerator Generator r F: Fa

Frequencg If" frequencg Multiplier Multiplier 1P1 Rafa Frequency Frequencg Divider Divider F02 Hi ER 3J2 Modulator Modulator M1 "2 Generator Generator Generator Frequencg frequencg I frequencg Divider Divider i Divider fins I t a 61 51; 53

frequency frequenug frequencg H1 Multiplier H13 Multiplier firm Multiplier 5 Bifr it I I ask $5 Modulator Modulator l Modulator l M M M; l l t INVENTOR Wladimir Janiiuchewskg ATTORNEY METHUD FOR FORMING A LINEAR COMBINA- TION 3 OF FREQUENCZES AND APPARATUS FOR CARRYING OUT THIS METHOD Wladimir Ianouehewsky, Paris, France, assignor to Ebauc'hes-S. -A., Neucha'tel, Svtitzeriarrd Application April 30, 1953, Serial No. 352,129 Claims priority,-appiication France 'May 14, 19 52 10 Claims. (Cl. 250-36) This invention concerns a method-for fanning-from a-series of frequencies differing each by little from a mean frequency, a linear combination, in particular the sum or'a mean of said frequencies.

This invention is also concerned with an apparatus for carrying 'out this method.

It is usual in high precision" measurements to measure the same value with a number of separate gauges, because the value measured by one gauge only is subject to accidental errors due to the accidental variations of the gauge. If, however, the mean value of measurements carried out by a number of separate gauges is taken, the probable accidental error of the result will be smaller thanthe accidental error occurring in the result of a measurement by one gauge ma if the gauges are identical the result will be the arithmetical mean of the different 'siri'gle measurements, whereas in case' of gauges with different characteristics it maybe of interest rerun-r1 a'mean wherein the different measurements are given different weight; If e. g. the measurements by n gauges of the same value are mi, m2, mu it may be of interest to take the folowing mean vallue m of themeasurements:

m=a1m1+a2m2+ +afim1t ar-l-az-l- +an=1 and whereby a, az', an are the coe'fficients or weights attached to the corresponding gauges. V

The'same result might advantageously be obtained by one single measurement with a gauge the size or value of which equalsthe-mean of the values 141, 142, uh ofthe different gauges'having the same nominal value or size.

This invention is concerned with frequency generators and more particularly with a methodfor forming from wherein a"serie'sof frequencies the sum and/or the meanffrequen'cy. According to the invention it is possible to form automatically fromn frequency generators with the fifequencies f1, f2, f1; respectively (these frequencies diffaring but little from the nominal frequencies of the generators) a frequency wherein there is no restriction for the 'coeflicientsa'i, a'z, az,-. an except for they must be rational numbers, that is they are to be the quotient of two integers 611 3? a2= %j7 a,,=; i

wherein A1, Az, An and B1, B2, En are integers'. This restriction is of purely formal characterand means no limitation from a physical point of view of the generality of Equation 1 and for the application of the invention I Ina first form of the invention a frequency is multi plied and/or divided in afir'st stage by integers infrequency'multipliers and frequency dividers of well known 2,781,450 Bar ts! fab-.12Q2

use

type, thereby producing from a frequency f'a'ii ewfl 'euen'c'y A whereby the coefficients A and B are integers. Practicallythe frequency is first multiplied byA in a frequency multiplier of the ratio A and then divided by B in a frequency divider of the-ratio B.

Equation '1 may be written'as fellows:

Fm=F1+F2+ +Fn 2') It is now possible to form in a second stage the surnof the n frequencies F1, F2, Ffi'obtained each fromth'c frequencies f1, f2, fn in'the first stage by multiplication and/or division V In certain forms of thisfinvention the frequency 'gen er'a'tors are identical in which case all-the frequencies f1, f2, fn have the same nominal value f and the coefiicients a1, a2, all all equal In thiscase according to a second form of thisinvention the sum of the frequencies f1+f2+ +f1t is formed in a first stage and this siiniis divided by n in a second stage.

It is seen that in the above mentioned forms of the invention the sum of a series of frequenciesis formed, which are either'of the same nominal value and differmg in fact very little'frem each other, orwhich are integral multiples or'integr'al parts of another frequency of the series.

According to this invention an auxiliary frequency is required for forming the sum of several frequencies, which is in nojs imple'relationship to oneof the frequencies tobe added. In general the auxiliary frequency will be chosen much higher than thehighest of the frequencies to be added.

In order to forn'i the sum of n frequencies F1, F2, PM, it is sufficient to know how to sum up two frequencies, e. g; Fi'and F2. The resulting frequency may then be added to a third frequency, e. g. F3 and so on step .by step 'uiitil all the frequencies are summed up. Makinguse' or the a'ssoeiativ law of the'addition partial sums may be formed and these partial sums may again be summed up iii-order to form the whole sum.

In order m fofm-thsuinjof two frequencies F1 and F2 the'auxiliary'frequency Fm which is much higher than any of thfrequencies Pi and F2 is modulated by the frequeneiesFl and F2 separately, whereby the following frequency spectrums are produced:

Fat-F1, Fr, Fm-I-Fl and I I u F:cF2, Fa, Faz-i-Fz By means'of a bandpass filter or of a high pass filter from-which the frequency Fi-l-Fz is isolated by means of a l'owpass-fil't'er met a bandpass filter. 1

Exactly the same result would have been obtained by isolating first the frequencies Faz-Fl and Faz-I-FB by means of suitable filters and to modulate these frequencies in a second stage.

It is an important advantage of this invention that the auxiliary frequency Fa: must not be stabilized because it has no influence on the result as may be seen from the above formulas.

If a relatively great number of n frequencies F1, F2, F1: are to be added up, this is advantageously done in making use of the associative law of the addition in order to economize modulators and filters. Thereby the frequencies are first added by pairs as follows: (F 1+F2), (Fad-F4), (F(7L-1)+F7L) if n is even, and (F1-I-F2), (Fad-F4), F11. if n is odd. This new series of frequencies obtained by adding pairs of the fundamental frequencies are again combined in pairs, and so on until two partial sums may be combined in a last modulator in order to make the total sum.

Some possibilities of carrying out the invention are described below by way of example and having reference to the drawings in which Fig. l is a diagram showing the elements of an apparatus for adding up two frequencies F1 and F2.

Fig. 2 is a diagram showing the elements of an apparatus for forming the mean of three frequencies f1, f2, and f3, and

Fig. 3 shows the circuit diagram of an apparatus capable to form the mean of two frequencies f1 and f2.

Figs. 4 and 5 are diagrams illustrating the way in which the apparatus of Figs. 1 and 2 may be combined with frequency multipliers and frequency dividers.

The frequencies F1 and F2 to be added to the apparatus of Fig. 1 are produced according to the above described method from two frequencies f1 and f2 of which latter the mean frequency is to be produced, by multiplying and dividing these frequencies in classical (not shown) equipment according to the formulas In Fig. 1 G1 and G2 are frequnecy generators generating the frequencies F1 and F2 respectively, Gr is the generator for the unstabilized auxiliary frequency Fa: and M1 and M2 are modulators. The frequencies F1 and F1 are fed into the modulator M1, whereas the frequencies F2 and F1: are fed into the modulator M2. Filters B1 and B2 respectively are connected to the outputs of the modulators M1 and M2. The filter B1 is a band pass for the frequency (Fm-l-Fl) of the frequency spectrum produced in the modulator M1 and the filter B2 is a band pass for the frequency (F1IF2) of the frequency spectrum produced in the modulator M2.

The frequencies (F2+F1) and (Fa-F2) from the filters B1 and B2 respectively are fed into a modulator M4 followed by the filter B4 which is a band pass for the frequency (F1+F2) of the frequency spectrum produced in the modulator M4 from the frequencies (Fm-l-Fl) and In this way the sum F1+F2 of the frequencies F1 and F2 is obtained.

The Figures 2 and 3 show other forms of the invention, in which the frequencies are first added and then divided by the number of frequencies in order to obtain the mean frequency. v

In Fig. 2 E1, E2 and Ba are frequency generators of the same nominal frequency f but generating in reality """a'rsmso the frequencies f1, f2 and f3 respectively differing slightly from the frequency f, and of which the mean frequency is to be formed by the apparatus. G1; is the generator for the auxiliary frequency Fa:-

The auxiliary frequency Fm is first modulated by the frequencies f1, f2 and is in the modulators M1, M'2, and M's respectively. Filters B1, B'2 and B's are connected to the modulators M'1, M'2 and M's respectively isolating e. g. the frequencies (Fw'+f1), (Fa:--f2) and (F:rf3) respectively.

The frequencies (Fzc-l-fl) and (Fe-f2) are fed into the modulator M4 in which the frequency (f1+f2) is produced amongst others. This frequency is isolated by a filter B4 and fed into a modulator M5 in order to modulate the frequency Fa: which is also fed into this modulator. The modulator M5 is connected to a band pass filter B5 for the frequency (Fz+f1+f2).

The frequencies (F+f1+f2) and (Fm-f3) from the filters B5 and B's respectively are fed into another modulator Ms followed by a band pass filter Be for the frequency (f1+f2+f3) produced amongst others in the modulator Me.

The frequency (f1+f2+f3) is fed into a frequency'divider D of the ratio 3 at the output of which the frequency the arithmetical mean of the three frequencies f1, f2 and f appears.

In the circuit shown in Fig. 3, which is suitable for forming the arithmetical mean of two frequencies f1 and f2, E1 and B2 are frequency generators of the same nominal frequency but generating in reality frequencies f1 and f2 differing slightly from the frequency f. Gm is the generator for the auxiliary frequency F:r- T1, T2 and T3 are modulator hexodes and T4 and T5 are triodes. F is a band pass filter for the frequency f.

The cathodes of the tubes T1, T2 and T3 are connected to earth by means of polarizing resistors R1, R2 and R3 respectively, these resistors being bridged by condensers C1, C2 and C3. The screen grids of the tubes T1, T2 and T3 are connected to a high voltage source HT through resistors R4, R5 and R6. The screen grids are connected to earth by means of condensers C4, C5 and Cs. Three oscillatory circuits L1C1, L2Cz and LaCs respectively constitute the loads of the tubes T1, T2 and T3. These loads form together with the plate resistance of the corresponding tubes band pass filters for the frequencies (Fe-H1), (Fa-f2) and (f1+f2) respectively.

The frequencies f1 and f2 generated by the generators E1 and E2 are fed to the grids G1 and G1 of the tubes T1 and T2 respectively after being brought to a suitable voltage in the potentiometers P1 and P2. The frequency Fa: is applied to the grids G3 and (Y3 of the tubes T1 and T2.

The frequencies (Fm-I-fl) and (Fm-f2) appearing on the plates of the tubes T1 and T2 respectively are fed through condensers C7 and C8 to the grids G"s and G1 of the modulator tube T3. The resistors R7 and Rs are the grid leak resistors of the gridsG"1 and G"a. Due to the modulation of the frequencies (F:c+f1) and (Fm-f2) in the tube T3 and due to the filter formed by the oscillatory circuit L3C3 together with the plate resistance of the tube T3 the frequency (fr-H2) appears on the plate of T3.

This frequency (f1+f2) serves for synchronizing a multivibrator through the condenser C9, the potentiometer P3 and the resistor R9. This multivibrator is formed by the tubes T4 and T5. The plate of tube T4 is connected to the grid of tube T5 by means of a condenser C10 this grid being connected to earth by a resistor R10. The plate of tube T5 is connected to the grid of tube T4 by means of a condenser C11, this grid being connected to earth by a resistor R11. The cathodes of the tubes T4 and T5 are directly earthed. The plates of thesetubes arefed from the high .voltagesourceHT through .resistors R12 and R12.

The condensersCro .and C11 and the resistors R :and R11 are so designed .that thevmultivibratorT i, T5 is freely oscillating at a frequency slightly below the frequency f. If, however, the multivibrator is synchronizedlby the frequency (fr-l-fz) of suitable amplitude it will oscillate at the frequency which is very close to the frequency f. If required, this frequency appearing on .the plate of the tube T4 may be 'freedfrom its harmonic oscillations in a filter F connected to the plate T4.

Figs. 4 and 5 illustrate the way inwhich linear combinations of the type may be obtained from frequencies f1, f2, fn generatedin generators of different frequency stability. The circuits of Figs. 4 and 5 correspond to the circuits of Figs. 1 and 2 respectively but differ from those circuits in that frequency dividers and multipliers are'inserted between the generators and the first modulators.

Fig. 4 shows a circuit for forming a mean of two'frequencies F1 and F2 generated in generators G1 and G2 respectively. The frequency F1 from G1 is applied 'to a frequency multiplier FM-1 of well known'type having a multiplying ratio A1. The frequency F1A1 resulting from this frequency multiplication is fed to a frequency divider FDi of "well known type having a dividing ratio B1 so that a frequency will result from this frequency divider, this frequency being fed to a modulator M1 in which this frequency is intermodulated with the auxiliary frequency Fa: from the generator Gr. In the same manner the frequency F2 generated in the generator G2 is multiplied by a factor A in a frequency multiplier FM2 and the frequency Az'Fz resulting from this frequency multiplication is divided in a frequency divider FDz by a factor B2 so that a frequency of is fed to the second modulator M2 inwhich it is intermodulated with the auxiliary frequency Far. The modulators M1 and M2 correspond to the modulators M1 and M2 of the circuit illustrated in Fig. 1 and the frequencies are then added in the manner described with reference to Fig, 1 for forming'the linear frequency combination Fig. 5 illustrates a part of a circuit similar to the circuit shown in Fig. 4 but for forming a linear combination of three frequencies f1, f2 and f3 generated in generators of different stability E1, E2 and E3. These generators as well as the modulators M'1, M'z and M's shown in Fig. 5 correspond to the same elements of the circuit shown in Fig. 2. The frequencies f1, f2, f3 are first divided in frequency dividers FDs, PD; and FDs by factors B1, B2 and B3 respectively and are then multiplied in frequency multipliers FMs, FM4 and FMs respectively by factors A1,. A2 and A3 respectively for producing.fre-

quencies A i A BI-f B22); and

While I have illustrated and described in detail certain forms of the invention, it is to be understood that changes may be made therein and the invention embodied in other structures. I do not, therefore, desire to limit myself to the specific constructions illustrated, but intend to cover my invention broadly in whatever form its principles may be embodied.'

Whatl claim is:

1. In a system for forming a linear frequency combination froma number of initialffrequencies, a frequency divider and 'a frequency multiplier connected in cascade for each of the said initial frequencies, each of the said initial frequenciesbeing divided and multiplied in one of .the said frequency dividers and frequency multipliers respectively whereby a changed frequency results for every initial frequency, an oscillator producing arr-auxiliary frequency, at least one frequencyadding circuit each comprising modulator means for so combining two of the said changed frequencies with the said auxiliary frequency that sum and difference frequencies of the said auxiliary frequency and each one of the said changed frequencies are generated, two filter means for selecting asum frequency and a difference frequency respectively, modulator means for so combining the said selected sum frequency and difference frequency that a sum and a difference beat frequency are produced and an output filter means for selecting the said difference beat frequency which equals the sum of two of the said changed frequencies, a number of frequency adding circuits being provided for adding all the said changed frequencies and partial sums of changed frequencies so that the total sum of all the said changed frequencies is formed.

2. In a system for forming a linear frequency combination from a number of initial frequencies, frequency changers comprising a frequency divider and a frequency multiplier connected in cascade, one frequency changer being provided for each of the said initial frequencies and each of the initial frequencies being changed to an intermediate frequency in one of the said frequency changers, at least. one frequency adding circuit for-adding two frequencies and comprising first modulator means, first filter means connected to the output of the first modulator means, second modulator means connected to the output of the first filter means and second filter means connected to the output of the second modulator means, an oscillator generating an auxiliary frequency, each two of the said intermediate frequencies being so combined with the said auxiliary frequency in the said first modulator means that two sum and two difference frequencies are generated, one sum frequency being selected in one of the said first filter means and one difference frequency being selected in another of the said first filter means, a so selected sum frequency and difference frequency being so combined in the said second modulator means that the sum beat frequency and the difference beat frequency are generated and the difference beat frequency which equals the sum of two intermediate frequencies being selected by the said second filter means, a number of adding circuits being provided sufficient for adding each two of the said intermediate 7 frequencies to form a partial sum of two intermediate frequencies and for further adding partial sums of intermediate frequencies with at least. one intermediate frequency to form the total sum of all the intermediate frequencies.

3. In a system for forming a linear frequency combination from a number of initial frequencies independently generated in individual frequency generators, one frequency changer being provided for each initial frequency for changing it by a rational coefficient to form an intermediate frequency, and means for adding all of the said intermediate frequencies for forming a linear combination from the said initial frequencies.

4. In a system for producing a highly stable frequency, a number of individually operating frequency generators operating at the same nominal frequency, a frequency changer comprising the cascade connection of a frequency divider and a frequency multiplier connected to each of the said frequency generators, each generator frequency being changed in one of the said frequency changers, the sum of the changing ratio of the said frequency changers being 1 and the changing ratios being different for at least some of the frequency changers, all the output frequencies from the frequency changers being added to form a highly stable frequency combination from the said generator frequencies.

5. In a system for producing a highly stable frequency, a number of individually operating frequency generators, a frequency changer comprising the cascade connection of a frequency divider and a frequency multiplier for each of the said frequency generators, each generator frequency being changed in one of the said frequency changers by a coefficient determined by the ratios of the frequency divider and frequency multiplier of the frequency changer, all the output frequencies from the frequency changers being added to form a frequency combination from the said generator frequencies.

6. In a system for producing a frequency of high stability, at least two individually operating frequency generators producing each an initial frequency, each of the said generators being connected to a frequency changer comprising a frequency divider and a frequency multiplier in casacde connection, each of the said initial frequencies being changed in one of the said frequent changers by a ratio determined by the dividing ratio of the said frequency divider and the multiplying ratio of the said frequency multiplier for producing an intermediate frequency from each of the said initial frequencies, and a frequency adding circuit adapted for addition of a number of independent frequencies equal to the number of intermediate frequencies, all of the said intermediate frequencies being added up in the said frequency adding circuit for forming a frequency combination of high stability from the said initial frequencies.

7. In a system for producing a frequency of high stability, at least two individually operating frequency generators producing each an initial frequency, each of the said generators being connected to a frequency changer, each of the said initial frequencies being changed in one of the said frequency changers by a predetermined ratio for producing an intermediate frequency from each of the said initial frequencies, and a frequency adding circuit adapted for adding a number of frequencies equal to the number of intermediate frequencies, all of the said intermediate frequencies being added up in the said frequency adding circuit for forming a frequency combination of high stability from the said initial frequencies.

' 8. In a system for forming a linear frequency combination from a number of initial frequencies, a number of frequency changers, one frequency changer being provided for each of the said initial frequencies and each of the initial frequencies being changed to an intermediate frequency in one of the said frequency changers, at least one frequency adding circuit for adding two of the said intermediate frequencies and comprising modulator means for intermodulating two of the said intermediate frequencies and filter means for selecting the sum of the said two intermediate frequencies, a number of adding circuits being provided sufficient for adding each two of the said intermediate frequencies to form a partial sum of two intermediate frequencies and for further adding partial sums of intermediate frequencies with at least one intermediate frequency to form the total sum of all the intermediate frequencies.

9. In a system for forming a linear frequency combination from a number of initial frequencies, at least one frequency adding circuit for adding two frequencies and comprising first modulator means, first filter means connected to the output of the first modulator means, second modulator means connected to the output of the first filter means and second modulator means, an oscillator generating an auxiliary frequency, each two of the said initial frequencies being so combined with the said auxiliary frequency in the said first modulator means that two sum and two difference frequencies are generated, one sum frequency being selected in one of the said first filter means and one difference frequency being selected in another of the said first filter means, a so selected sum frequency and difference frequency being so combined in the said second modulator means that the sum beat frequency and the difference beat frequency are generated and the difference beat frequency which equals the sum of two intermediate frequencies being selected by the said second filter means, a number of adding circuits being provided sufficient for adding each two of the said initial frequencies to form a partial sum of two initial frequencies and for further adding partial sums of initial frequencies with at least one initial frequency to form the total sum of all the initial frequencies.

10. In a system according to claim 9 a frequency divider having a dividing ratio equal to the number of initial frequencies added, the said total sum of all the initial frequencies being fed to the said frequency divider and divided in the same.

References Cited in the file of this patent UNITED STATES PATENTS 2,405,765 Smith Aug. 13, 1946 2,602,159 Wirkler July 1, 1952 2,617,039 Young Nov. 4, 1952 2,735,983 McLeod Feb. 21, 1956 FOREIGN PATENTS 890,233 France Feb. 2, 1944 410,663 Italy Apr. 19, 1945 625,358 Great Britain June 27, 1949 

